Enhancing the Fire Resistance of Steel Framed Structures Through Beam-slab Interactions

摘要

The current prescriptive approach of evaluating fire resistance has a number of drawbacks, not the least of which is that it does not account for the redistribution of forces that occurs between various members. In a steel frame structure with a concrete floor slab, the beam-slab composite action can significantly enhance the fire resistance of the steel beams. This paper presents a set of numerical simulations to illustrate the effectiveness of beam-slab interaction in enhancing the fire resistance of the steel beams under realistic fire and loading scenarios. The factors considered in the parametric study include fire scenario, load level, concrete strength, geometric conditions, slab thickness, and cover thickness to the reinforcement. Results from parametric studies indicate that the concrete slab can significantly enhance fire resistance of steel beams under realistic fire and loading scenarios. By properly accounting for the contribution of the slab in fire resistance calculations, it is possible to eliminate fire protection to secondary beams in many practical situations.